How to Choose a Good One?
Is Looking at SPF Enough when Choosing a Sunscreen?
When sunscreens were developed in the 1920’s, the main purpose is to allow people to stay longer in the sun without getting sunburns. SPF (Sun Protection Factor) indicates the protection against sunburns – which is mainly caused by UVB, so SPF is an indicator for UVB protection but not so much for UVA. It is only in more recent years that we realized the skin damaging effects of UVA. Whereas all sunscreens provide excellent UVB protection, most sunscreens do not have high UVA protection. Labeling of UVA protection, unlike SPF, is not mandatory in most countries.
How to Choose a Sunscreen with Good UVA Protection?
Look for sunscreens with UVA labeling such as PPD (Persistent Pigment Darkening) or UVA-PF. These are the equivalent of SPF for UVA. It is common for sunscreens to use the Japanese PA grading system (from + to +++). PA+ = PPD 2 to 4; PA++ = PPD 4 to 8; PA+++ = PPD higher than 8.
Sunscreens which have labels like “broad spectrum”, “UVA/UVB protection” may not give adequate UVA protection as there are no strict regulations concerning the use of these terms. It is better to go for one with specific PPD or PA labeling.
Are Sunscreens with High Protection Level Harmful to the Skin?
There is no evidence to show that high protection level sunscreens have any detrimental effects to the skin. Often in making a sunscreen product with good UVA protection, its UVB protection (=SPF) is inevitably pushed up as well.